This application requests five years of funding to continue our efforts to understand the factors that are sustaining the high prevalence of HIV infection, HIV risk behaviors and high incidence of AIDS among Puerto Rican drug users. The overall study goal is to develop and test models that assess the effects of parental drug use and depression, adolescent substance use and psychopathology, as well as HIV risk behaviors, and the mediating effects of cultural, familial/ extra-familial and personal factors on transitions and turning points that define the movement from early to late adolescence. Drug using (n=375) and non-drug using parents (n=375) and one of their offspring (n=750), 13 to 15 years of age, residing in poor neighborhoods comprise the group of study participants. This application proposes a prospective study design with a nested ethnography. Data will be collected by multiple assessment strategies: interview protocols and structured psychiatric interviews using the Spanish version of the Diagnostic Interview Schedule for Children Version 2.1 (DISC 2.1) to assess substance use/ abuse, depression and conduct disorders among adolescents at baseline and in year 2, 3 and 4. The Spanish version of the substance abuse and depression scales of the Composite International Diagnostic Interview (CIDI) will assess substance abuse and depression among parents at baseline and in year 2 and 3. These diagnostic data, along with annual interviews of parents and adolescents will cover a critical and wide range of topics related to participants' life events and transitions; such as school and work experience, drug and alcohol use/ abuse, criminal behavior, coping mechanisms (e.g., social support, self-esteem and mastery), and depressive symptomatology. These data and the information collected through the in-depth interviews conducted by our ethnographic team will provide specific information with which to assess adolescent transitions, especially substance use/ abuse and HIV risk behaviors and adaptation to their expected roles as they move from early to late adolescence.